The Electoral College's intention was to balance large states' power with small states' desire to not let large states run everything. The college had nothing to do with slavery or the Three Fifths Compromise. Slave states gained more power in the Electoral College from the extra 3/5 votes, but a) the compromise itself had nothing to do with the Electoral College's creation or design, and b) 3/5 of a vote gave less power to slave states than their preference, a full vote for each slave.